Propulsion means for speedboats



Feb. 27, 1951 J. NAPOLI 2,543,253

PROPULSION MEANS FOR SPEEDBOATS Original Filed Nov. 15, 1945 INVENTOR. JOHN NAPOL/ ATTORNEY l aienied Feb. 27, 1951 UNITED STATES .e'rur i s up" I Divided and this application August 1, 1950, Serial No. 176,940 p v Thi invention relates to propulsion means for speed boats.

The propulsion means embodying the present invention comprises duplex units mounted on the hull of a boat at opposite sides of the keel. The two units each comprise aligned propeller tubes within which a propeller shaft and a propeller are rotatably supported. Water inlet and outlet means at ends of the tubes make it possible for water to flow freely through the tubes as the prepellers are rotated.

The present invention provides novel duplex propulsion means forspeed boats or the like, having identical propulsion units of the characterized which are arranged in opposed relation beneath a boat hull.

Other objects or advantages of the present invention will be pointed out hereinafter, indicated in the appended claims, or will be obvious to one skilled in the art upon an understanding or the present disclosure. For the purpose of this an" plication I have elected to show herein certain forms and details of propulsion means for speed boats embodying my invention. It is to be understood, however, that the embodiment of mi invention herein shown and described is for illustration purposes only, and that therefore it is not to be regarded as exhaustive of the variations of the invention.

This is a divisional application of my now pending application entitled Speed Boats, Serial No. 628,023, filed November 13, 1945, now U. S. Patent No. 2,530,718 of November 21, 1950.

In the accompanying drawings:

Fig. 1 is a bottom view of a speed boat having my duplex propulsion means mounted thereon;

Fig. 2 is an enlarged horizontal sectional vi w taken centrally through one of the propulsion units;

Fig. 3 is a sectional view taken on the line 33 of Fig. 2; and

Fig. l is a diagrammatic illustration showing the manner in which the propeller tubes are secured in place by bracket means.

In the drawings I have shown the two units of my duplex propulsion means mounted on the hull l of a suitable speed boat or the lik at opposite sides of the keel 2. While my duplex propulsion means is particularly suitable for use with speed boats of the type shown in my aforesaid patent application it is also adapted for use with various other types of boats.

Supported at opposite sides of the keel 2 on the bottom of the boat's hull by means of suitable brackets 3 are two open propeller tubes 4. The

2 Claims. (Cl. 115-46) brackets 3 each comprise semicircular end portions 5 which extend partially around the tubes 3 and are secured rigidly thereto by rivets, bolts or other suitable means. The brackets 3 preferably extend through the hull of the boat and are supported thereby.

The propeller tubes l are arranged in substantially parallel positions with each other and with respect to the boats longitudinal center line. Each propeller tube l comprises aligned forward and rear sections to and to which are arranged and to end with the rear end of the forward section do tapered sufficiently as at to to form an annular water inlet opening it for the fiovv of water into the rear section so. The inlet opening 5 being in communication with the openings in the forward and rear sections to and in avoids any possible back pressure and at the same time provides means for admitting additional water into the rear section during the operation of the propeller therein. Suitable means such as a plurality of rigid straps or bars 5 bolted or riveted to the adjacent ends of the tubular sections and 4b maintain the said sections in fixed relationship.

Axially arranged in the sections ta and in of each tube i is a shaft 8 having a bevel gear 55 and a propeller l0 secured thereto. The propellers it are positioned in the forward ends of the rear sections ib. Each shaft 8 is rotatably sup ported in streamline bearings i i which are axially supported in their associated tubes by radial members I2. lhe elongated bearings l l which are supported in the forward sections are tapered. In mesh with the bevel gears ii are similar gears 13 secured to shafts it which are connected in the usual manner to the boats engine or power plant, shown at it. A duplex rudder it for guiding the boat is operated in the usual manner by suitable means on or within the boat. During the normal operation of the boat the tubes are at all times in submerged positions where surface waves will not vary the relative traction of the propellers iii. The tubes t prevent any side currents or a change in the direction of the boats forward movement from varying the operating efiioiency of the propellers. Thus the provision of tubular enclosures within which the propellers operate, makes it possible for such propellers to operate with uniform eficiency, irrespective of a change in the direction of the forward movement of the boat or the presence of side currents. The stability of the boat is considerably increased by providing a propulsion means of the type embodying the present invention. The forwardly tapered forward bearings H are constructed and arranged to direct circular streams of water rearwardly into the rear section 4b as the boat moves ahead. The water flowing into the forward ends of the rear sections 41) from the forward sections 4a and through the inlet openings 6 assumes circular formations as it meets the propellers II].

It will be noted that the duplex propulsion units embodying the present invention are so positioned with respect to the hull l of the boat that they are fully submerged in the water at all times, ir respective of whether or not storm conditions prevail. Such propeller units provider means which operate uniformly and with efiiciency at all times, thereby avoiding such instability and erratic movements as ordinarily occur when in rough seas a boats propeller is carried out of the water.

What I claim is:

1. In propeller means for speed boats; or the like, a rear tubular propeller housing,- adapted, to be mounted on a boat beneath the. water lineand having axial bearing means therein, a forward tubular housing axially aligned, with the rear tubular housing and having a taperedv rear end portion positioned adjacent the forward, end, of the first mentioned tubular housing the said tapered rear end portion of the forward tubular housing being spaced from the, rear tubular housing, an elongated tapered bearing member sup ported axially in the forward tubular housing with its pointed end pointed. forwardly, a, propeller shaft supported at its forward end in the tapered bearing member and at its rear end in bearing means of the rear housing, a propeller secured to the shaft, and gear means on the shaft.

2. In propeller means for speed boats or the like, an elongated tubular propeller housing adapted to be mounted on the hull of a boat beneath the water line, thesaid housing comprising axially aligned forward and rear tubular sections arranged end to end in spaced relation, the said forward section having a tapered rear end portion of smaller diameter than the forward end of the rear section, whereby an annular water inlet opening is provided between adjacent ends of the sections, tapered bearings secured in fixed axial positionsinthe forward and rear tubular sections, a rotatable propeller shaft journaled in the bearings, a propeller secured to the shaft and positioned in. the rear section of the tubular housing, and means connecting the shaft to a source of po er,-

JOHN' NAPOLI,

REFERENGES' GITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 451,086 Toliver Apr. 28,1891 1,267,506 Bowen May 28,1918 1,545,723 Zwiesler July 14, 1925 1,802,860 Zwinkel Apr. 28, 1 931 

